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Biomedical subjects

H Kurz

Publications and source records attributed to H Kurz.

At least 19 recordsLinked to original sources
PubMed1995

Proliferation pattern of capillary endothelial cells in chorioallantoic membrane development indicates local growth control, which is counteracted by vascular endothelial growth factor application.

The density and distribution of whole mount BrdU-anti-BrdU labeled endothelial cells (days 6-15) in the chick chorioallantoic membrane (CAM) was analyzed with computer-assisted microscopy. A significant loss of proliferative activity was noted after day 10: the density of labeled nuclei (in 10(-2) mm-2) decreased from a median 7.78 (days 6, 8, 10) to 2.42 (days 12, 14, 15). CAMs initially showed random patterns of labeled endothelial cells, but changed to clearly focal patterns after day 12. A regular arrangement of labeled nuclei was never seen. After application of vascular endothelial growth factor (VEGF) to the day 13 CAM, a significant increase in proliferative activity (11.50) and a random distribution of labeled endothelial cells was observed on day 15. Development of CAM precapillary vessels was assessed in terms of length density (in mm-1, mean +/- standard deviation), which was augmented three-fold from day 6 (1.22 +/- 0.05) to day 14 (3.54 +/- 0.23) and then remained nearly constant. VEGF application from day 13 to 15 raised arterial length per unit area to 4.53 +/- 0.77. It is concluded that normally a local regulation of endothelial proliferation and differentiation develops in the CAM, which doubles capillary endothelial cell density but simultaneously adapts to the decreasing need for endothelial cells, and thus maintains the quasi two-dimensional vessel pattern. However, proliferative foci persist in the capillary layer after day 10, and precapillary vessel density continues to increase until day 14. VEGF enhances DNA synthesis in all capillary endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantoin↗
PubMed1990

Classification applied to smears in hormone cytology.

Hormone cytology smears have been classified using a standard method of graph theory. The Euclidean distance was chosen as a suitable measure of the dissimilarity between smears. Maximum cliques were defined as groups to which no further element can be added without invalidating the group-defining distance. Both the type and number of cells found in the smear influence the classification. The absolute number of cells appears to be especially appropriate for the discrimination of the different proliferation stages of vaginal epithelium. However, the elaboration of an adequate sampling procedure is necessary for obtaining smears from the lateral wall of the vagina, as well as for the improved preparation of the smears themselves.

Female↗
PubMed1989

[Description and assessment of a rapid new method for measuring erythrocyte sedimentation rate].

A new method for the rapid photometric determination of the erythrocyte sedimentation rate (ESR) is described and compared with the Westergren technique. The basis of this method is the development of a new physical equation valid for transport processes, in which sedimentation processes can be described by means of a linear regression analysis. After the mathematical transformation, the measured ESR data follow a linear function. The apparatus evaluated measures within a few minutes the velocity profile of the ESR over a distance of about 2 X 10(-4) meter by kinetic determination of the optical density of a short blood column filled in a small cuvette. A microprocessor calculates the linear regression and derives the one and two hour values by extrapolation. The correlation of this method with the standard Westergren technique, determined over 20 days is acceptable (R = 0.95; n = 368). The reproducibility of the same sample (n = 20) is better than that of the conventional procedure. The reproducibility determined with different instruments (n = 20) is comparable to the precision of the Westergren method. The practical value of this new time- and blood-saving, well standardized method for an efficient patient-care is discussed.

Blood Sedimentation↗
PubMed1989

Which granules can be stained with azure B and eosin?

The standardized stain composed of pure azure B and eosin, as published by Wittekind and colleagues in 1986, demonstrated granules in neutrophilic leucocytes that were much coarser than those seen after staining with conventional Romanowsky-Giemsa methods. These granules belong to at least two classes. Their identification cannot be achieved by means of the morphologic characteristics of single granules; a multivariate analysis of the granulation as a whole, and a comparison with specifically stained primary granules is required. In particular, this study on unbiased cell samples showed that with Wittekind's method, the primary granules in peripheral neutrophils are stained. Further study of clinical smears revealed an enhanced dye uptake by the secondary granules. The staining behavior of the granules is related to the leukocyte count.

Azure Stains↗
PubMed1989

[Experiences with improved preservation solutions for historic and modern anatomic preparations].

Basing on experiences made at the Anatomical Museum Basel often arising difficulties of conservation of ancient anatomical preparations are described. Criteria are named which allow the recognition of specific problems of various preparations, and the adequate solutions for fixation and conservation are given. These solutions, the compositions of which are described in detail, are suited for historical as well as for modern wet preparations. Thus, it is possible to save and stabilize also delicate preparations of former times, even those with faint hues can be renovated which afterwards show an increase of contrast and an improved preservation of colours. Furthermore, techniques are indicated for mounting and preservation of preparations in special containers made of acrylic glass. By means of these methods, the preservation of preparations as well as the cleaning and change of solutions are markedly improved.

Anatomy↗
PubMed1988

Binding of drugs to human skin: influencing factors and the role of tissue lipids.

For a series of ten drugs with different physicochemical properties, binding to human skin (epidermis and corium) was determined. Epidermis was obtained by suction blistering, and corium was sliced with a microtome (0.2 mm). Binding experiments were performed in dialysis chambers, containing labelled drug solutions. All drugs investigated were bound to epidermis and corium. With one exception, epidermal drug binding was significantly higher than corial binding. Nevertheless, a good correlation between binding of drugs to both skin fractions could be found. In a range from 10(-7) to 10(-3) mol L-1 binding of drugs to both skin fractions is linear and not saturable. A good correlation was found between binding and lipophilicity of drugs, determined as the partition coefficients between an organic phase (octanol or heptane) and phosphate buffer of pH 7.0. The results show that binding to epidermis and corium is not saturable and depends on lipophilicity of drugs, indicating unspecific binding. Further binding experiments were performed with lipid-depleted tissue. Since drug binding to lipid-depleted samples and control samples differ only to a moderate extent, it is suggested, that tissue lipids play a marginal role on drug binding. Hence, drugs are bound to human skin by other components like proteins.

Chemical Phenomena↗
PubMed1985

Changes in fibrinolytic activity during the course of a single hemodialysis session.

Cardiopulmonary bypass, a form of extracorporeal circulation, markedly increases blood fibrinolytic activity. Accordingly, we measured the effect of hemodialysis, another form of extracorporeal circulation, on fibrinolytic activity in 13 patients with end stage renal disease during and after a single hemodialysis session. Total fibrinolytic activity on fibrin plates, which reflects plasminogen activator levels, was below normal prior to dialysis, rose well above normal at one hour, and then dropped gradually so that just prior to the end of a dialysis session it was still significantly elevated. Within 30 minutes of the end of dialysis, fibrinolytic activity fell rapidly, approaching predialysis levels. In contrast, 5 patients studied before and 3 hours into a peritoneal dialysis session showed no change in their subnormal levels of plasminogen activator. Plasminogen and alpha-2 antiplasmin levels did not change significantly during the course of hemodialysis. Thus, hemodialysis, but not peritoneal dialysis, transiently increases fibrinolytic activity without consuming plasminogen, a pattern consistent with the release of tissue type plasminogen activator.

Adult↗
PubMed1981

Acute cecitis.

Explore the source record for details and available documents.

Acute Disease↗
PubMed1980

Binding of drugs to muscle tissue: dependence on drug concentration and lipid content of tissue.

For a series of 16 drugs the extent of binding to homogenized rabbit skeletal muscle was determined by means of ultrafiltration. The percent bound of basic drugs was essentially constant over a 100- to 1000-fold concentration range, i.e., binding was linear. Among weak organic acids the fraction bound decreased with increasing drug concentration for furosemide, warfarin, phenylbutazone, salicyclic acid and sulfonamides. Fitting of the binding data by Langmuir isotherms appeared to be inappropriate for several reasons. A simple power function (Freundlich isotherm) was found to satisfactorily represent the experimental data. Drug binding properties of muscle homogenate were altered following extraction of lipids with acetone. Lipid-depleted muscle tissue exhibited a decrease in binding of chlorpromazine and propranolol, whereas binding of imipramine was unchanged. Binding of phenytoin, warfarin and sulfadimethoxine was enhanced in lipid-depleted muscle. The results suggest that binding of drugs to muscle tissue cannot solely be explained in terms of partitioning into lipids.

Animals↗